With the complicity of the intense solar activity,
the month of December 2015 represented one of the geomagnetic period most turbulent of our monitoring time. The PC1 pulses detected in
the week before Christmas are an example.
Geomagnetic activity detected - Kiruna
Geophysical Institute (Sweden ) http://www.irf.se/maggraphs/puls.php
PC1 pulsation are evidenced in dashed white square. They are
identified with a letter: the same that will be used to
follow.